Fluid heat exchange apparatus



Dec. 24, 1935. v J MILLAR 2,025,066

FLUID HEAT EXCHANGE APPARATUS F iled June a, 1935 2 Sheets-Sheet 1 INVENTOR James F Millar A'ITORNEY Dec. 24, 1935. J. F. MILLAR FLUID HEAT EXCHANGE APPARATUS 2 Sheets-Sheet 2 Filed June 6, 1933 lnfl ill IIIIIIIII INVENTOR James F Mil/a1 k BYE l ATTORNEY Patented Dec. 24, 1935 UNITED STATES PATENT OFFICE FLUID HEAT EXCHANGE APPARATUS Application June 6, 1933, Serial No. 674,494

8Claims. (Cl. 122-235) This invention relates to furnaces and is more particularly concerned with improvements in furnace walls in which fuel burners are mounted.

The use of high capacity turbulent and mix- 5 ing fluid fuel burners in modern furnaces has resulted in such high temperature conditions adjacent the burner walls that severe operating and maintenance difliculties have been experi; enced. These conditions are further aggravated 10 when preheated air is used for combustion, giving rise to a further tendency to still higher temperature conditions.

Under such conditions, when an uncooled refractory wall with burner passageways is used,

15 spalling, softening, and melting of the refractory has occurred. This has resulted, in some cases, in frequent shut-downs for expensive repairs and has caused the limitation of the operation to lower rates of heat liberation and furnace temperatures, in other cases.

- Such difliculties have been encountered in spite of the fact that the burner passageways have been undesirably restricted at least in one direction. Such restriction has involved excessive combustion losses. It is an object of this invention to provide a furnace with a burner wall having circular burner'passageways, elongated in a direction normal to the furnace wall and adequately cooled by the wall tubes which delineate the elongated passageways. It is also an object of the invention to provide such burner wall passageways with converging and diverging portions of greater length than the thickness of the furnace walls, and for guiding the fiow of air and fuel.

It has been proposed to cool burner walls by means of fluid conducting tubes but no effective arrangement of tubes and refractory has been 40 suggested which will extend the cooling effect into close proximity to the burner passageways and at the same time provide an arrangement of fluid cooling elements which will be easily cleanable.

It has been proposed that short wall tube sections and secondary headers be placed between adjacent burners, but the resulting exposure of such secondary headers to radiant heat has made this proposal ineffective. Other proposals have 50 also been proven ineffective.

Another object of this invention is to provide furnace burner walls which will overcome the difliculties of the prior art structures without the use of secondary headers between adjacent burn- 55 ers. It is also an object of this invention to provide a burner wall in which wall cooling tubes extend uninterruptedly past a plurality of bum-'- ers with their portions adjacent the burner passageways arranged with extended surfaces to protect the walls of the passageways by adequate '5' cooling action.

A further object of the invention is to provide a furnace burner wall in which uninterrupted wall cooling tubes not only prevent excessive destruction of the burner walls but also cooperate with fuel feeding parts of thegburners to form and maintain a circular fuel and air passageway for each burner.

An embodiment of the invention is shown in the accompanying drawings, in which: Fig. 1 is an upright transverse section through apparatus embodying. the present invention.

Fig. 2 is a detail view of a front elevation of a portion of a furnace wall taken from the inside of the furnace and showing the arrangement of the wall cooling tubes and the burners.

Fig. 3 is a transverse section on the line 3-3 through the burner wall.

Fig. 4 is an upright transverse section taken on the line 4-4 of Fig. 2.

Fig. 5 is a sectional detail view of an illustrative structure similar to that shown in Fig. 3, Fig. 5 disclosing the use of headed studs on the wall tubes.

In the drawings there is disclosed a boiler fur- 30 nace 10 arranged beneath a bank'of steam generating tubes l2. The walls of the furnace are preferably protected against overheating, the rear wall l4 being delineated by spaced tubes l6 connecting upper and lower headers l8 and 20. This wall is preferably connected into the boiler circulation by suitable connections 22 and 23.

-In the construction shown, the wall of the furnace 24 is a burner wall. Vertically arranged burners indicated generally by the numerals 26 and 28 are shown disposed in that wall so as to project burning fuel into the furnace. Spaced tubes 30 for the'burner wall preferably extenduninterruptedly from the lower header 32 to the upper header 34. These headers are preferably connected into boiler circulation by suitable connections one of which is indicated at 33.

As indicated in the drawings the lower ends of the wall tubes 30 are in a row extending lengthwise of the wall 24 and the header 32. At their upper ends they are also arranged in a single row along the wall. At the burner positions some of thetubes are bent out of their single row alignment so as to extend around the bent portions of greater displacement.

burners and to act to cool the furnace walls forming the burner passageways.

As indicated in Figs. 2 and 3 the wall tubes 36 and 38 nearest the center line of the burners have These tubes are not only bent out of the plane of. the row of tubes beyond the burner passageways, but they are bent divergently with reference to the center lines of the burners. The extent of this bending is indicated by the dotted lines 40 and 42 in Fig. 3. As here shown their most widely spaced portions 44 and 46 are located nearer the exterior of the furnace than any of the other tubes. They are positioned beyond the burner gas ring 48 and protected with insulating or refractory material 50. The tubes 52 and 54 located on opposite sides of the burner center line and adjacent the tubes 36 and 38 have their most I fwidely divergent portions indicated at 56 and 58 in Fig. 3. The position of their-ends beyond the burners are indicated by dotted lines at 54 and 52 in'Fig. 2. The widely diverging portions 56 and 58 are preferably positioned closely adjacent the burner gas ring and are arranged with respect thereto so as to form a part of a burner passageway having diverging and converging portions for guiding air and fuel. Their sides presented inwardly of the furnace are preferably providedwith radially arranged studs 64 which are welded to the tubes.

- outwardly of the tubes 52 and 54 successive pairs of tubes 66 and 68 are arranged in a manner similar to the arrangement previously described. The studs 64 welded on the tubes adjacent to the burner passageway are preferably covered with refractory 10. It will thus be seen that the furnace wall forms burner passageways elongated in a direction normal to the wall and adequately fluid cooled and protected from spelling and melting. The protective refractory is shown in .Fig. as thermally and structurally bonded to the wall tubes by headed studs 61 which are advantageously welded to the tubes.

Intermediate the adjacent burners the wall tubes 36 and 38 are bent convergently so as to have a spacing comparable with the spacing of the tubes beyond the burner opening. The next adjacent tubes 52 and 54 have a less extensive curvature underneath the burners, and are arranged to approach the normal spacing of the tubes (relative to the tubes 36 and 38) beyond the burners.

At positions directly above and below the burner openings there are shown preformed blocks 12. These blocks may be secured to the wall tubes in any suitable manner so as to form a continuation of the burner passagewaywalls formed by the refractory which is placed upon the bent tubes which have been previously described.

- .end.

While the invention has been described with reference to the particular embodiment shown,

' it is to be understood that the invention is not limited thereto. It is of a scope commensurate with the scope of the subjoined claims.

What is claimed is:

1: In combination, a furnace wall having a flaring fuel port therein, means for discharging a fluid fuel through said port, a refractory annulus adjacent said fuel port, and a plurality of pairs of wall cooling tubes having substantially single plane bends embracing said fuel port and determining its flaring conformation and arranged in heat transfer relation to said annulus.

2. In a steam boiler, a furnace wall having a flaring fuel port therein, means for discharging fluid fuel through said port, a refractory annulus adjacent said port, and a plurality of pairs of vertically arranged water tubes having portions above and below said fuel port arranged substantially parallel and intermediate substantially single plane bends embracing said port and determining its flaring configuration, said intermediate bends being arranged to hold said annulus in position and in heat transfer relation therewith.

3. In a furnace for the combustion of fuel in suspension, a burner, a ring of refractory material outlining a flaring burner opening in a wall of the furnace, wall cooling tubes in approximate parallelism above and below the opening and having substantially single plane bends substantially circumscribing the ring, the bent tubes reinforcing the refractory and maintaining it inoperative position and being in good thermal contact with the refractory to protect it by their cooling effect.

4. In a furnace having a ceramic wall, a refractory annulus outlining a burner opening in the wall, a plurality of pairs of wall cooling tubes in parallel positions beyond the opening and bent to substantially single plane bends circumscribing the refractory andretuming .to their parallel positions on the other side of the opening, and metallic studs welded to the wall sidev of the bends, the bent tubes and studs reinforcing the refractory and maintaining them in operative position and being in good thermal contact with the refractory to protect it by their cooling effect, the tubes being located on the furnace side of the wall. I

5. In a furnace, a wall including cooling tubes spaced uniformly in a row at their upper and lower ends, a fuel burner directing a fuel stream into the furnace through a circular and flaring opening elongated transversely of the wall, a group of the tubes having substantially single plane bends projecting in parallelism obliquely of the row and outwardly of the wall to outline a flaring throat for the burner opening, radially ar-. ranged studs having enlarged heads at their tube ends and welded to the burner opening sides of the bent portions of the tubes, and a refractory annulus applied to the tubes and studs as a plastic to provide an incandescent wall during the operation of the furnace, there being a group of single plane bent tubes on each side of the axis of the burner. V

6. In fluid heat exchange apparatus, a furnace wall including cooling tubes spaced uniformly in a row at their upper and lower ends, a burner for projecting fuel through a flaring burner port of a minimum diameter greater than the distance between the remote sides of four consecutive tubes, a circular gas ring embedded in the wall, at least two of the tubes on each of the opposite sides of the burner axis having parallel substantially single plane bends extending outwardly of the furnace toward one side of the burner and arranged to delineate a "continuous port wall between the gas ring and the adjacent straight or unbent tube, radial metallic studs welded to the port sides of the bends, and refractory material applied as a plastic over the studs.

7. In combination, a furnace wall having spaced wall cooling tubes arranged in a wall forming row and'connected into fluid circulation, 76

' a furnace .nace, adjacent wall means for burning fuel in suspension in the furnace, some of said tubes being bent outwardly of the furnace and out of their row formation so as to embrace a furnace wall port, the bent tubes returning to their well row formation beyond the port, metallic studs nace sides of the bent portions of the tubes and extending toward the axis of the port, and refractory material positioned over the furnace faces of the tubes between the studs and installed as a plastic filling the spaces bent portions of the wall cooling tubes delineating port extending through the wall and elongated in a direction substantially normal to the Wall.

8. In combination, a furnace wall having spaced wall cooling tubes arranged in a wall forming row and connected into fluid circulation, i

means for burning fuel in suspension in the. furwelded to the furport, extended between the tubes, said tubes being oppositely bent outwardly of the furnace and out of their row brace a furnace wall port, the bent tubes extending uninterruptedly past the port and returning to their wall row formationbeyond the surface metallic studs welded to the furnace sides of the bent portions of the tubes and extending toward the axis of the port, and refractory material positioned over the furnace installed as a plastic filling the spaces between the tubes and maintained by the studs, said bent portions of the wall cooling tubes delineating a formation intermediate their ends so as to emfaces of the tubes between the studs and furnaceport extending through the wall and 15 elongated in a direction substantially normal to the wall.

JAMES F. MILLAR. 

